Control for wireless receiving sets



March 12, 1929. M|TTELL 1,704,802

CONTROL FOR WIRELESS REC EIVING SETS Filed May 1925 3 Sheets-Sheet l WIIMW M M M 24.

March 12, 1929. E, M|TTE| 1,704,802

CONTROL FOR WIRELESS RECEIVING SETS Filed May 1925 5 sheets-sheet 2 March 12, 192 9. B. E. G. MlTTELL 8 CONTROL FOR WIRELESS RECEIVING SETS Filed May 1925 3 Sheets-Sheet 3 Patented Mar. 12, 1929.

UNITED STATES PATENT OFFICE.

BRENCHLEY ERNEST GEORGE MITTELL, OF IVER, ENGLAND, ASSIGNOR TO VICTOR TALKING MACHINE COMPANY, OF CAMDEN, NEW' JERSEY, A CORPORATION OF NEW JERSEY.

CONTROL FOR WIRELESS RECEIVING SETS.

Application filed May 2, 1925, Serial No. 27,614, and in Great Britain May 5, 1924.

This invention relates to an improvement in or modification of the controls for wireless receiving sets and other electrical apparatus described in my application for Patent Serial No. 749,789, dated November 13th, 1024.

In the specification of that application is described an apparatus whereby all the variables, in a wireless receiving set or other electrical apparatus, such as condensers, inductances, couplings and the like may be ad justed by turning a single knob. l

The object of the present invention is to provide means whereby an apparatus c111- bodying this control may be converted or adjusted to suit different working conditions. For example, in the case of a wireless receiving set it is desirable to be able to alter the reaction coupling according to whether the transmitting station is near or far away and this alteration may be etlected by the means forming the subject of the present. invention.

In the control apparatus described by way of example in the earlier application a (tlllt is mounted so as to be rotated synchronously with the variable condenser, so that it can vary the coupling of the reaction coils correspondingly and so keep the reaction constant or approximately so, to Whatever wave length the set may be tuned by varying the condenser.

In order to be ablewto vary the reaction coupling in different ways according to the distance from the transmitting station, raised or steepened portions may be provided on the cam which controls the reaction couplin so that the extent or rate of movement of the reaction coil, relatively to the aerial inductance coil, during the operation of the control is altered. The arrangement is of course equally applicable for the adjustment of other variables such as inductances, condensers and the like.

It will be understood that just as in the apparatus described in theearlier application it is proposed to tune the aerial once and for all according to the location of the receiving set, so also the cam or cams which controls or control the reaction coupling will be shaped once and for all by means of the raised or steepened portions to suit certain circumstances and for receiving from certain stations.

The present invention accordingly consists in an im rovement in or modification of the controls or wireless receiving sets and other electrical apparatus described in the earlier application above referred to wherein one or any number of the cams, rotated through the medium of the control member to vary the electrical values of the variable components of the apparatus, is or are furnished with one or more raised or steepcned portions on its periphery, or their peripheries, so that the degree of variation of the electrical value of the components, corresponding to said cams. for a given movement of the control tnber' is changed.

The invention is illustrated in the accompanying drawings in which Fig. 1 is a plan view of the control apparatus described in the main application.

Fig. 2 is a plan view of a part of Fig. 1.

Fig. 3 is sectional elevation on the line A-l5 of Fig. 1.

Fig. 4 is a sectional elevation on the line (-I) of Fig. 1.

Fig. 5 illustmtcs a cam such as used with the control apparatus described above. provided with a raised or stcepcned portion in accordance with this invention.

Figs 6 and 7 illustrate alternative forms.

Referring to Figs. 1, 2 and 3 of the drawings, 1 is a-finger operated wheel adapted to rotate the shaft 2 through gears 3 and l. Upon shaft 2 are keyed or otherwise rigidly secured four aerial inductance coils 5, (i, 7 and 8 arranged in the manner clearly shown in 1 and 3 and each corresponding to a certain band of wave lengths. The ends of these coils are connected with pairs of segments 9, 10 and each coil is put in circuit in turn by stationary brushes 11 which rub on the segments 9, 10 which rotate with the coils. At the rear end of shaft 2 is a gear wheel 12 which meshes with and drives a similar gear Wheel 13 rigidly mounted on shaft 14. 15 and 16 are cams mounted upon shaft 14 and rotat-ing therewith.

The cam 15 operates thev condenser 17 by rocking a bell crank lever 18-1) about shaft 2, a toothed segment 20 on the end of the arm 19 of the bell crank lever engaging with a gear Wheel 21 on the condenser shaft 22. Cam 16 controls the movement of the reaction coil 23 with the reaction coil 23 secured thereto.

From Figs. 3 and 4 it will be observed that the certain range of movement and the arrangeher 0 ment is such that both the condenser 17 and the reaction coil.23 can be moved over that range While one of the aerial inductance coils 5, 6, 7 or 8 is in circuit. i If now it is for example desired to vary the extent or rate of movement of the reaction coil 23 to vary its coupling with the aerial inductance coil, one or more raised or steepened portions are formed upon the periphery of the cam 16, These may be formed by plates 30, secured to the cam by screws or bolts 31 passed through holes 32 in the cam 16 (see Fig. 5). The plates may be provided with long slots 33 to permit the adjustment "of the lates radially of the cam, and a numf holes 32 may be provided spaced around the cam so that the plates 30 may be attached in an position around the centre of the cam. here a number of plates are required some may be mounted 'upon the front of the cam and some on the back (see Fig. 7 Fig. 6 illustrates a cam which during a complete revolution provides for only one range-of movement of the component which it controls. The plates 30 may be of any desired shape, the two shown at 34 and 35 in Fig. 6 being given only by way of example, the edge, however, which isto form part of the peripherv of the cam being of such shape as to give the necessary lift.

If convenient the original cam may be replaced by a circular plate such as 35 in Fig. 7 with spaced holes 32in it to which the plates 30 can-be readily attached.

I claim:

1. In an electrical apparatus for radio reception, a tuning device comprising a yariable cou ling, a single control member, means inclu ing a cam m'ember operatively connecting said control member with said variable coupling and adapted to move both members of said coupling at different rates, and means for varying the cam surface.

2. In a radio apparatus, a variable tuning coupling, a single control member, means including a cam operatively, connecting. said control member with said variable coupling and adapted to move both members of said coupling at different rates, and means adapted to form a steepened portion on the periphery of said cam.

3. In a radio apparatus, a variable tuning 'cou ling, a single control member, means inclu ing a cam operatively connecting said control member with said variable coupling, and adjustable means forming one or more raised portions on the cam surfaces to vary the rate of relative movement of the members of said coupling. I

4. In a radio a paratus, tuning means comprising a variab e coupling, a single control member, means including a cam operatively connectin said control member with said coupling for adjustingboth members of the coupling in predetermined relationship, and means for varying the adjustment of said coupling including a plate secured'to said cam and adjustable relatively thereto.

. 5. In a radio apparatus, tuning means comprising a variable coupling, a single control member, means operatively connecting said control member with said couplin' and including a cam, said means being a apted to adjust both members of said coupling, and ashaped plate mounted on and variable radially of said cam to form a steepened portion on the cam periphery.

6. In a radio apparatus, tuning means comprising a variable coupling, a single control member, means operatively connecting said control member with said coupling and including a cam, said means being adapted to adjust both members of said coupling, and a shaped plate mounted on and variable radially of said cam and about the center thereof to form a steepened portion on the cam periphery. r

' 7. In radio apparatus, tuning means comprising a plurahty of movable inductance coils adapted to be successively inserted in circuit, a coil coupled with that inductance coil which is in circuit and movable relative thereto, a control'member, means for moving .said coupled coils at diiferent rates includinlgl thereto, a single control member, means adapted to move both of said coupled coils relative to one another at different rates'and including a cam operatively connected with one'of said coils, and ineans adapted to form a steepened portion on the cam periphery to vary the adustment of the rate .of relative movement of said coils.

In testimony whereof I have 'signed my name to this specification.

BRENCHLEY ERNEST GEORGE MITTELL. 

